To develop a selectively grown silicon oxide film with low stress for micromachined devices, a novel liquid-phase- deposition (LPD) technique is proposed. LPD-oxide can be grown as the supersaturated concentration of Si(OH)4 reaches a low-limit. The concentration can be controlled y the deposition temperature and the quantity of boric acid (H3BO3) added. Owing to the difference in low-limit between Si and photoresist, a selective LPD process window is thus formed. The selective-growth mechanism has been proposed and confirmed. Detailed understanding is instructive to apply the technology to MEMS devices and microfabrication.